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The Sun's 10th Planet... Sedna?

Posted by ryuzaki0 on from the well-that-remains-to-be-seen dept.

dsanfte writes "While NASA remains intentionally vague, promising only a news conference Monday, The Australian has the details. The new planet, dubbed Sedna after the Inuit goddess of the sea, is 3 billion km further from the sun than Pluto, and is slightly smaller at 2000km in diameter. This discovery has apparently reignited the debate as to how big a solar object must be in order to qualify as a 'planet', but it is significant nonetheless."

28 of 636 comments (clear)

  1. A lot of astronomers don't want to count Pluto by Anonymous Coward · · Score: 5, Interesting

    So why should we start counting an even smaller "planet"? Pluto gets grandfathered in, and that's it.

    1. Re:A lot of astronomers don't want to count Pluto by WorkEmail · · Score: 5, Funny

      I say we put up a huge sign next to the Sun that says "You must be at least this big (insert huge red line) to ride this ride."

    2. Re:A lot of astronomers don't want to count Pluto by Jesus+2.0 · · Score: 5, Insightful

      Pluto should be labeled an asteroid since it's smaller than even our own moon.

      Frankly, I don't understand this line of reasoning. Why does it matter, with regards to whether something is a "planet" or not, whether that thing is bigger than, for example, our moon?

      And "asteroid"? Pluto is far, far larger than anything currently considered an "asteroid".

      Jupiter and Saturn both have moons that are bigger than Mercury. Do you not consider Mercury to be a "planet", either?

      What if Jupiter had a moon bigger than Earth? That's not unimaginable; would Earth then not be a "planet"? In fact, would then nothing be a "planet" except Jupiter, Saturn, Uranus and Neptune?

      I frankly don't see what's wrong with (something like) a "planet" being a non-star that's orbiting (directly) around a star. Sure, that makes for some seriously small "planets" relative to what we're used to, but at least it's not an arbitrary and useless definition like (no offense) yours.

      And anyway, if you want to add back in your preferred amount of arbitraryness, you can always start referring to "major planets", "minor planets", and so forth.

    3. Re:A lot of astronomers don't want to count Pluto by r2vf · · Score: 5, Informative

      IMO, Pluto should [shouldn't?] be labeled an asteroid since it's smaller than even our own moon [wikipedia.org].

      An interesting point, though to be fair, its an arbitrary cutoff. There are moons elswhere in our solar system larger than Mercury, which is indisputably a planet, for example. Also its worth pointing out that our moon is large enough that it and Earth are sometimes called a double planet. Consider this, Luna does not orbit Earth as near the equator as is usual among most other moons. Also, peculiar to all 138 known moons with the exception of Charon, it possesses an orbit where the effect of the Sun's gravity is greater than that of Earth's. Without their host planets, they would float off, wheareas the moon would continue orbiting the sun quite contently.
    4. Re:A lot of astronomers don't want to count Pluto by SEWilco · · Score: 5, Funny

      Yes, it would be so much better to just reshape the incoming rock into a long needle so we have destruction confined to only two tiny little spots, including the spot on the opposite side of the Earth.

  2. Woop de fucking do! by Operating+Thetan · · Score: 5, Funny

    Cue conspiracy theories, New Age freaks, Planet X believers and other idiots. Still, at least this discovery has the redeeming quality of completely fucking up astrology

    --
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    1. Re:Woop de fucking do! by Snowspinner · · Score: 5, Funny

      Yeah, it'll probably cost a lot to reprint all the New Age ancient traditions to include a tenth planet.

      --
      Philip Sandifer's academic website
    2. Re:Woop de fucking do! by Anonymous Coward · · Score: 5, Interesting

      Yeah, it'll probably cost a lot to reprint all the New Age ancient traditions to include a tenth planet.

      Ten Planets? You haven't been keeping up with here astrology has been going the last twenty-fove years. I know astrologers who use twenty planets, most of which are imaginary. [ Dutch School of Astrology. Germans School of Astrology. The Planets of Alice Bailey, and related flakes.]

      This, of course, ignores the two hundred or so asteroids which new age astrologers use. And don't forget the plethora of comets, meteor showers, deep space objects, and other things that may, or may not exist.

      And to be sure that you haven't forgotten anything, there are umpteen "Arabic Parts", Midpoints, Orbs, harmonics, ( or something like that) etc.

      In short, roughly 10^8 objects that no self-respecting astrologer would omit, if one believes in the validity of all the books on astrology that have been published.

    3. Re:Woop de fucking do! by cybermace5 · · Score: 5, Interesting

      Wanna know what will REALLY give the conspiracy theorists, New Age freaks, etc? "Sedna" is "Andes" spelled backwards! Everyone knows the advanced Inca civilization lived in the Andes mountains, and there are more than enough wacky theories about the Incas involving aliens and whatnot. Oooh...why is an Inuit god named after backwards-Andes...are the Inuits actually Inca refugees? They're close the Pole, too, and there are already crazy theories about a hole to the interior of the earth where advanced civilizations live, and the Eskimos are somehow related....

      Yeah, can't imagine a worse name, really. Backwards-spelled stuff is pure gold in the conspiracy community.

      --
      ...
    4. Re:Woop de fucking do! by S.O.B. · · Score: 5, Funny

      But then the evolutionists would respond with, "10 planets, ten fingers. Coincidence?"

      --
      Some of what I say is fact, some is conjecture, the rest I'm just blowing out my ass...you guess.
  3. I wonder what is so important.... by dealsites · · Score: 5, Interesting

    I wonder what is so important that NASA is going to wait until Monday. Maybe they will be unveiling something else at the same time?

    --
    Real-time deal updates

    1. Re:I wonder what is so important.... by AnamanFan · · Score: 5, Interesting

      It's a standard rule of Public Relations. Never announce anything between Friday at 4pm till Monday at 8am.

      The reason being that news outlets are not at full capacity during the weekends, so any news announced over the weekend won't get as much coverage. If NASA announced the news today, it will be covered on the Sunday evening news, and never again since that piece of news was already done, even when not many saw it.

      You can notice this practice when someone famous dies over a weekend. There will be an immediate announcement saying that the person is missing or very ill or something of the sort, then make the announcement on Monday.

      --
      AnamanFan - Trying to find the Truth, one post at a time.
  4. whew! by odano · · Score: 5, Funny

    Thank god I am out of elementary school. Memorizing 9 planets was hard enough, but 10! They have got to be kidding.

    1. Re:whew! by Anonymous Coward · · Score: 5, Funny

      My very educated mother just sent us nine pizzas, sucka - Mr. T

  5. for comparison purposes: by Anonymous Coward · · Score: 5, Informative

    Pluto is 2300 km diameter, ranges from 4.3 to 7.4 billion km from the sun.

    http://www.windows.ucar.edu/tour/link=/pluto/stati stics.html

  6. It's a Kuiper object... by meringuoid · · Score: 5, Insightful
    ... and the last I heard was that it was about the size of Charon. I doubt it will ever be recognised as a planet - we already have Quaoar out there and swarms of other little Plutinos.

    Whether Pluto is 'really' a planet or just a big Kuiper object seems to be a silly argument. Even if it's not justifiable, we'll call Pluto a planet out of tradition.

    --
    Real Daleks don't climb stairs - they level the building.
    1. Re:It's a Kuiper object... by Gutboy_Barrelhouse · · Score: 5, Informative
      No. Charon is slightly smaller than Quaoar.

      Sedna is over 4 times the size (volume) of Quaoar.

      Whether it's a planet is a silly argument, but even so, "we already have Quaoar" is really irrelevant.

    2. Re:It's a Kuiper object... by RobertFisher · · Score: 5, Informative
      The question becomes even more convolved once we move outside the solar system, since we now know of a wide diversity of systems, of which our own solar system is only one particular instance. (And perhaps not even typical at that.) We know that there are objects extending all the way down from massive stars (around 100 Msun) to hydrogen-burning stars like our sun to brown dwarfs to planets. Clearly any definition of a planet must apply not only to our solar system, but also to these extrasolar systems. Some of these systems are much like our own (for instance, they may contain a brown dwarf orbiting a star, or a planet orbiting a star), and some (including a few systems of low enough mass to qualify as a planet) are "free-floaters" -- just sitting out there by themselves in space.

      I think ultimately the question is whether there is a single continuous "initial mass function" of isolated objects or not. The best idea as to how stars acquire their initial mass is that turbulence in the interstellar medium, which exists on all scales, establishes a power-law distribution of initial masses. Every once in a while, you get a very strong shock which passes by inside a giant molecular cloud and forces the collapse of a large region which then goes on to form a massive star. But more typically, you form stars more like our sun. And just as rare as massive collapses are very small mass ones which go on to form isolated brown dwarfs and free-floating planets. If this model holds up to be true, then we are all mincing words in our definitions of isolated systems, since they are all manifestations of the same universal formation process.

      However, to avoid the difficult question of formation mechanisms, an IAU working group of some of the most respected people in the field established a working definition to define by fiat what it means to be a brown dwarf, and a planet. Extrasolar "planets" are those objects orbiting a star which are beneath the deteurium-burning limit -- regardless of how they are formed. "Brown dwarfs" are defined to be those which burn deuterium but not lithium, and "sub-brown dwarfs" (NOT free-floating planets!) are defined to be those isolated objects which do not burn deuterium. Even the working group itself admitted that this definition was not satisfying to a single member of the group, and so it is likely it will be replaced at a later time with something more physically-motivated. The "planet/planetismal/KBO" distinction was pushed back to our own solar system, since it will be some time before anyone sees anything that small in another system.

      Also of interest is the following link, which gives a history of previous claims for additional planetary members of our solar system : SEDS.

      --
      Science, like Nature, must also be tamed, with a view turned towards its preservation.
  7. What happened to the naming convetion? by Snowspinner · · Score: 5, Interesting

    I thought planets were Roman gods. It's not even like we've run out of them. We can still find Vulcan (Mulciber if you want to avoid rabit Trekkies), Juno, Minerva, Apollo (You can call this one Phoebus if you want to avoid confusing it with space probes), Diana, Vesta.

    And that's before you start getting slightly obscure ones like Janus, Bacchus (Or Liber), Fanus, Quirinus, Pomona, or Vertumnus.

    --
    Philip Sandifer's academic website
    1. Re:What happened to the naming convetion? by Sqwubbsy · · Score: 5, Interesting

      Wasn't 'Apollo' considered the sun. Remember, this wasn't just a 'naming convention' but actual mythology. Apollo drove the chariot of the sun across the sky. Mars, the god of war, appeared in certain places at certain times, same with Venus.
      Now that Roman mythology isn't really considered religion (outside of Berkeley) it can be a nice tradition. I mean, it's not lik the Inuit have really contributed to Western Culture except for, I guess, hockey and lacrosse.

      --
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  8. Re:Back to grade school for retraining... by thomasdelbert · · Score: 5, Informative

    Correction - Neptune was farther from Pluto from January 21, 1979 to Feb. 11, 1999 but at this time Pluto is farther from the sun than Neptune.

    Of course, there's debate as to whether Pluto-Charon is a planet with a moon, or a double planet...

    - Thomas;

    --
    ___ This sig is in boldface to emphasize its importance!
  9. There could be a lot of stuff out there by mbone · · Score: 5, Interesting

    Out in the Kuiper belt and the Oort cloud there are thought to be as many as one trillion objects - most small 1 to 10 km chucks of ice.

    The really interesting question is, what is the mass distribution ? (I.e., how does the number of objects scale with their mass ?) This is basically unconstrained by real data. All such cosmic mass distributions are steep, but many (for example, planets in the Solar System, Asteroids in the Asteroid belt) are dominated by the most massive bodies.

    If this holds true in the Oort cloud, in particular, there could be some pretty big objects. Even a Jupiter sized object might be able to hide from the Infrared surveys (the best way of detecting such an object).

  10. Re:How could by phch · · Score: 5, Insightful

    It's always been hard to see distant planets because they don't emit light. Hubble can see distant galaxies because they contain lots of luminous objects.

  11. on being a planet or something less... by joebeone · · Score: 5, Insightful

    My former advisor here at UC Berkeley, Gibor Basri, has a neat way of discriminating between planets and the lesser (comets, asteroids, etc.). His idea is that if the object has enough self-gravity to force it into a spherical shape, it's a planet... if it doesn't (like Mars' "moons"), it's something less.

    Here's a snipet:

    How can this be resolved? A consensus is slowly developing (I believe) for the following solution. We can first define what we mean by "planetary mass", and base this only on physical characteristics. Then we can include circumstance into the definition of "planet". I propose the following three definitions:

    FUSOR - an object that achieves core fusion during its lifetime.

    PLANEMO - a round non-fusor.

    PLANET - a planemo orbiting a fusor.

    [...]

    read on for his full article.

    The following is a draft of an article now published in the Nov/Dec 2003 issue of Mercury. Draft of Mar. 20, 2003.

    Defining "Planet" by Gibor Basri Univ. of California, Berkeley

    Even before they were civilized, people looked into the sky and recognized different celestial objects. The Sun defined daytime, and the stars provided a fixed background of faint, twinkling lights at night. Among them moved the Moon, and a few special steadier lights. The Greeks called those which moved "planets" (it is worth noting that the Sun and Moon were originally included, since motion against the stars was the defining characteristic). Most cultures have an analogous word for these "wanderers". Both the stars and the planets were thought to revolve around the Earth.

    After the Copernican Revolution, we recognize the Moon as the only body that orbits the Earth. The Sun is a very nearby example of a star, and the visible planets are other large bodies that orbit the Sun. We see them by reflected sunlight, while stars produce their own visible light. This understanding yields the dictionary (lay public) definition of the word "planet": a large heavenly body that shines by reflected light and orbits the Sun. In the past century we gained much understanding of our Solar System, and even visited most of the planets robotically. Yet today, professional astronomers find themselves unable to agree upon a succinct definition of "planet". Replacing "the Sun" with "a star" is obviously necessary now that many extrasolar planets have been discovered, but the problem goes well beyond that.

    Two recent controversies that found their way to the popular press illustrate further difficulties. One is the "Pluto controversy". This arose because of the discovery of a large belt of icy objects beyond Neptune. They are the outer remains of the original protoplanetary disk. This "Kuiper Belt" is a natural outcome of incomplete planet formation in the outer Solar System, and is the source of some of the comets we see. As Kuiper Belt objects (KBOs) were discovered in increasing numbers in the 1990s, including a population of "Plutinos" which share Pluto's orbital characteristics (somewhat different from the other planets), some astronomers began to suggest that Pluto itself (which shares many properties with, but is the largest KBO known so far) does not qualify as a planet. The recent discoveries of Varuna and Quaoar (which are KBOs half the size of Pluto, like its moon Charon) may presage the time when we find another Pluto-sized KBO.

    The current situation is much like that in the early 1800s, when the first asteroids were discovered. Ceres was originally hailed as the fifth planet, particularly since one in its position was expected from "Bode's Law" of planetary spacings. It lost its status within a few years, when other members of the asteroid belt began turning up. Herschel, who had been the only person to have discovered a new planet before then, aided the effort to demote Ceres. The arguments against its planeta

  12. Picture of new planet: by big_groo · · Score: 5, Funny

    Here----> .

  13. Inuit Contributions by Vagary · · Score: 5, Informative

    Hockey was invented somewhere in Europe or European North America in the 19th century. Lacrosse was invented by Indians near the St. Lawrence and is played on grass rather than snow, so I doubt the Inuit were involved.

    Inuit inventions include snowshoes, toboggans, dogsleds, kayaks, toggle harpoons, and various other tools for hunting and travelling in the North as well as snow and ice civil engineering techniques. Pretty impressive, I'd say, for a culture with almost no wood, rock, or metal. They've probably contributed as much as any other non-Eurasian colonialised culture, and they make some really cool art.

  14. Here, a rule that I propose.. planet versus other: by deathcow · · Score: 5, Interesting


    If it's big enough to assume spherical shape by the action of gravity, it's a planet.

  15. Re:Here, a rule that I propose.. planet versus oth by daeley · · Score: 5, Funny

    By that logic, Anna Nicole Smith qualifies. ;)

    --
    I watched C-beams glitter in the dark near the Tannhauser gate.